But we aren't seeing the wage growth that should come from such a low unemployment rate. Thus there's something wrong with the unemployment rate--and the answer is almost certainly the gig economy. We have a lot of people "employed" at jobs that are better than doing nothing but generally end up being below minimum wage in reality.
I don't have stats to back me up, but I believe that is more that there is a general trend in business to flatten organizations. Companies are eliminating middle management jobs that pay more.
That's been going on for a long time. I don't think it explains the current pattern.